Photocatalytic materials are drawing significant attention because of their potential for solving environmental and energy problems. Among these problems are finding ways to address the contributions of CO2 to global warming while still permitting increased energy consumption, as energy plays a critical role in the quality of life improvement and economic prosperity.
One potential avenue for reduction of greenhouse gases such as CO2 has been CO2 photoreduction using a photocatalyst in which CO2 is reduced to various less harmful products over the photocatalyst that is activated by UV radiation. To date, titanium dioxide (TiO2) is one of the most studied photocatalysts because it has shown the most efficient photocatalytic activity, highest stability, low cost, as well as low toxicity. In the photocatalytic reaction, electrons and holes are produced from TiO2 under UV irradiation. The electrons and holes subsequently interact with reactants (including CO2) to form the products.
However, CO2 photoreduction has only been performed using titanium dioxide (TiO2) with limited or qualified success. One of the problems in using unmodified TiO2 as a photocatalyst is that electron and hole recombination leads to low photoconversion efficiency. Although various modifications to the catalytic structure have been attempted, none of the modifications have created a commercially and industrially viable structure for CO2 photoreduction.
Hence, a continued need exists for a photocatalyst that improves the kinetics of a photoreduction reaction of CO2.